Europe’s drugs regulator has for the first time recommended a gene therapy medicine for approval.

Glybera, a treatment for patients who cannot produce enough of an enzyme crucial for breaking down fat, was backed by the European Medicines Agency's (EMA) Committee for Medicinal Products for Human Use (CHMP). This recommendation has to be endorsed by the European Commission before it becomes available, but it would be unusual for the Commission to reject the recommendation.

Gene therapy involves transferring genes into patients to treat their diseases. In this case Glybera uses a virus injected into a patient to deliver a working copy of a gene for producing lipoprotein lipase (LPL). LPL deficiency affect no more than one or two people in a million.

Back in 2004 China became the first country to approve a gene therapy product for commercial use, with a treatment for cancer. But Europe and the United States have yet to endorse any gene therapy treatments and the field has been plagued by issues such as carcinogenicity.

Jörn Aldag, chief executive of uniQure, the Amsterdam-based company that owns Glybera, says today’s announcement from the EMA is an “overdue signal” to the gene therapy community that things are changing. “It unlocks the potential,” he told Nature. “You will see more investment coming.”

‘Fantastic news’
Tim Coté, former head of the US Food and Drug Administration’s Office of Orphan Products Development and now an independent consultant, says the approval is "astounding, fantastic news. It puts Europe at the forefront.”

Glybera had previously received negative opinions from both the CHMP and the EMA Committee for Advanced Therapies (CAT), which advises on cutting edge treatments. However, after re-evaluating the treatment in just those patients who experience severe or multiple attacks of pancreatitis as a result of LPL deficiency, the CAT gave a positive opinion in June, and this has now been endorsed by the CHMP.

Tomas Salmonson, acting chairman of the CHMP, said in a statement that the “established ways” of assessing the risks and benefits of Glybera had been challenged by the rarity of the condition and uncertainties in the data.

“The evaluation of this application has been a very complex process, but the use of Glybera in a more restricted indication than initially applied for, which targets the patient population with greatest need for treatment, and additional analyses by the [CAT] have added to the robustness of the data provided and allowed the CHMP to conclude that the benefits of Glybera are greater than its known risks,” he said.

The CHMP recommendation was eventually given only under an ‘exceptional circumstances’ designation. This allows a treatment to be approved in the absence of large scale clinical trials, and is used for therapies targeting diseases that affect only small numbers of patients where large-scale trials are near impossible. Glybera has been tested on 27 patients in three studies. UniQure will have to set up a registry to monitor what happens to patients taking the treatment, which will be reviewed by the EMA.

Hot on Glybera’s heels is another gene therapy treatment which targets the immunodeficiency disorder ADA-SCID. However this is an ‘ex-vivo’ treatment which involves performing gene therapy on a patient’s extracted bone marrow cells and then injecting them back into the patient.

Now being supported by London-based drug giant GlaxoSmithKline, this treatment is just behind Glybera in the approval process, says molecular biologist Fulvio Mavilio, scientific director of the French biotechnology institute Genethon and one of those working on the treatment.

“These two examples of products in the two flavours in which gene therapy is available today – ex-vivo and in-vivo – made it to the final stage, which is great news for the entire field,” he says.

This article is reproduced with permission from the magazine Nature. The article was first published on July 20, 2012.